Experimental investigation of the effect of zirconium diboride (ZrB2) addition on mechanical properties of spheroidal graphite cast irons used in steering gearbox bodies

With the changing world conditions, automotive materials are also changing, and high strength, light and cheap materials come to the fore day after day. Due to their location on the vehicle, the steering boxes act as a bearing for the gear wheel systems. Wear and clearances occur as the ball and ball bearings in the steering gearboxes work under constant load. This wear and clearances cause the steering gearboxes to work noisily. To prevent these abrasions, it is necessary to increase the strength of the steering gearbox bodies. In this study, steering gearbox body produced from spheroidal graphite cast iron material by adding Zirconium Diboride at different rates (0%, 0.227%, 0.455% and 1.364%). Hardness, compression and abrasion test specimens were prepared from this material in line with standards, and then tests were carried out. Test samples with and without added Zirconium Diboride were compared in terms of both some mechanical properties (Hardness and compression) and wear. In the analysis of hardness test results, after adding 0.455% Zirconium Diboride, the highest measurement in the C sample was 243 HB. As the addition rate increased, the hardness measurement test values also increased. The highest compression value in sample C was 1438MPa, with a 0.455% addition rate. As the addition rate increased, it was observed that the compressive stress values increased in general. Wear tests were performed to examine the changes in wear volume, wear rate and friction coefficients. SEM device was used to determine the wear mechanisms on the worn surfaces of the samples. It was observed that the wear volume values increased as the load value increased.